Tom Hanks, Edward Norton, Brad Pitt set to make HBO's new miniseries 'Lewis and Clark'

HBO has officially greenlit the long-gestating project 'Lewis and Clark' miniseries from exec producers Edward Norton, Brad Pitt, Tom Hanks and 4 others.

Starring Casey Affleck as Meriwether Lewis and Matthias Schoenaerts as William Clark, the six-hour miniseries will chronicle the pair's exploration of the Louisiana Purchase, the Verge reported.

Production of the project, which is based on the book 'Undaunted Courage' by Stephen Ambrose, is scheduled to start sometime this summer, but there's no word yet on when it will begin airing on the network.

John Curran will be directing the miniseries and sharing writing duties with Michelle Ashford and Norton.

According to HBO, 'Lewis and Clark,' tells the story of America's first contact with the land and native tribes of the country west of the Mississippi River.

The miniseries follows the epic journey of the Corps of Discovery and its captains, Meriwether Lewis and William Clark, who traverse uncharted territory on a mission to deliver President Jefferson's message of sovereignty as they search for his fabled all-water route to the Pacific.

'Lewis and Clark' focuses not just on their incredible achievements, but also on the physical, spiritual and emotional toll the expedition takes on them.